Post a pic of underside of head, are the two shallow dimples still present on intake side? If not it has been cut to minimum thickness. If they are there and you keep it, take it to a machinist to pressure test for cracks, if good then clean up valves, replace any bad valve guides and all valve stem seals. If you go b35 then use the b35 head as ports are larger and it has dual valve springs. The loose oil pipe screw might still be okay, if it fell off you would lose oil to the cam and rockers.